I would scan into my computer around a hundred novels, as many scientific texts, the Bible, the Koran, a few telephone books (great for nouns). Say around a hundred, a hundred and twenty thousand pages. Then I’d use a simple random program to mix them all up, and make a few changes – such as taking out all the A’s. That way I’d have a novel which was also a lipogram. Next step would be to print it all out and read it through carefully a couple of times, underlining the important passages. Then I’d load it all into a truck and take it to the nearest incinerator. While it was burning I’d sit under a tree with a pencil and a piece of paper and let my thoughts wander until I’d come up with a couple of lines, for example,
“the moon rides high in the sky –
the forest rustles”
At first, of course, it wouldn’t be a novel so much as a haiku. But that doesn’t matter. The important thing is to make a start.

[i think i got this from a book of Eco’s essays, but i can’t find it and the internet doesn’t seem to know about it]